Personal Health

Personal Health

By Jane E. Brody

Published: July 2, 1997

DO door frames, telephone poles and the edges of buildings appear bent or crooked, as if you were looking at them through heat waves on a highway?

Do objects at a distance seem clear but those up close are blurry, or vice versa?

When you cover one eye, then the other, do you notice a change in the color or size of objects?

Is there a blurry or blank spot in the middle of your visual field, as if a flashbulb had just gone off in your face?

Do not assume that you need new glasses and can wait weeks for a convenient appointment. See your ophthalmologist right away. Accept no delays. Any of these visual distortions may be an early symptom of age-related macular degeneration, a loss of central vision that is the leading cause of legal blindness in the United States. Any delay in getting a proper diagnosis and starting treatments to slow or stop the progress of this disease can hasten the day when you may no longer be able to read, drive or recognize faces.

Even if you have no such symptoms, if you are over 50 and have not had your eyes examined for several years, make an appointment to do so now. The earliest stages of macular degeneration produce no symptoms, though early signs of this irreversible condition can be detected through a complete eye examination.

Problems of the Macula

The macula is a tiny, highly sensitive region in the center of the retina that allows you to see fine details when you look directly at something. The macula also contains an intense concentration of pigmented cells, which enable you to see colors. Without a properly functioning macula, your central vision becomes increasingly impaired, though you will retain peripheral vision in shades of black and white.

With advancing age, the macula is subject to deterioration in one of two ways. It may become thin and sprinkled with small yellow spots, called drusen, which show up during a retinal exam when your pupils are dilated. About 90 percent of age-related macular degeneration is this so-called dry form, which may progress slowly, rapidly or not at all. But eye specialists are unable to predict the likelihood or speed of progression. Therefore, everyone with early stages of this problem would be wise to follow suggestions that may keep it from getting worse.

The remaining 10 percent of cases, the so-called wet form of macular degeneration, are more serious and more predictable. They result from an abnormal growth of new blood vessels beneath the retina, which pushes up the macula like tree roots under a sidewalk. These vessels are fragile and may leak cell-damaging blood and fluids into this visually critical region, form scar tissue and cause a rapid deterioration of central vision.

Age and Other Causes

Macular degeneration is rare in people under 50, but its incidence rises with age. Nearly a quarter of people 65 and older have some manifestations of this disease.

A recent five-year study of 3,583 Caucasian adults from 43 to 84 by Dr. Ronald Klein and his colleagues at the University of Wisconsin in Madison found that 30 percent of adults 75 and older had early signs of the disease and 23 percent would develop the condition within five years.

As more people live to advanced ages, experts predict, the disease will affect 6.3 million Americans by 2030.

Heredity, race and a person's sex play a role in susceptibility to macular degeneration. Whites are more susceptible than blacks, and Hispanics and women are twice as susceptible as men in general. But the main underlying cause is oxidative damage to the delicate cells of the macula. This damage results from highly reactive substances called free radicals, which are continually formed within the body and through exposures to outside agents. People may be unable to counter free-radical damage if their diets are deficient in antioxidant-rich fruits and vegetables or if they consume a lot of alcohol or saturated fats and cholesterol.

Exposure to the blue and ultraviolet rays of sunlight also generates free radicals in the retina, especially in people with light-colored eyes.

Tobacco smoke is another source of free radicals and a major reason for the increase in macular degeneration among Americans. A study published last October in The Journal of the American Medical Association, which followed 21,157 initially healthy male doctors for at least seven years, showed that those who smoked a pack or more a day were two and a half times as likely to develop macular degeneration as those who had never smoked. Among men who were former smokers, the increase in risk was about 30 percent.

But smoking takes a more serious visual toll among women. A study in the same journal of 31,843 female nurses followed for 12 years showed that women who smoke 25 or more cigarettes a day also faced a risk of developing macular degeneration that was two and a half times that of those who had never smoked. The risk for former smokers, even 15 years after quitting, was twice that of women who had never smoked.

People with high blood pressure, heart disease or diabetes face a greater than average chance of developing macular degeneration because the circulation to their eyes is likely to be impaired.

Preventing the Damage

Several avenues of prevention should now be apparent. When you are outdoors during the day, be sure to wear sunglasses, ordinary glasses or contact lenses that block 90 percent of the ultraviolet rays; on sunny days, add a hat with a brim that shades your eyes. Do not start smoking, and quit if you already smoke. Men should limit their alcohol intake to six drinks a week, women to three. Follow the current recommendations for reducing saturated fats and cholesterol in your diet. Eat less meat and choose lean cuts. Discard the skin of poultry. Use low-fat and nonfat dairy products.

Most important, perhaps, is to eat lots of fruits and leafy green vegetables, which are rich sources of the carotenoids called lutein and zeaxanthin. These antioxidants are the only pigments found in the macula and the only carotenoids that are clearly associated with protection against macular degeneration.

A recent Government-sponsored study found that people who ate the most foods rich in lutein and zeaxanthin had a 43 percent lower risk of developing macular degeneration than those who ate the smallest amounts of such foods. The best sources of these protective carotenoids include kale, spinach and collard greens, followed by broccoli, green peas and leaf lettuce.

Zinc may also be a valuable protective agent. One study found that zinc slowed the progression of macular degeneration. Food sources of zinc include meat, liver, eggs, poultry, and seafood, followed by milk and whole grains.

Supplements of the potentially protective nutrients may be recommended for people who cannot eat enough of the foods that contain them naturally.

Chart: ''Protective Vegetables'' Vegetables high in carotenoids associated with a lower risk of macular degeneration. Chart lists various vegetables and their Lutein/Zeazanthin content. Chart/Diagram: ''AT A GLANCE: The Retina's Vulnerable Center'' A tiny, highly snsitive area in the center of the retina, the macula, enables you to see color and fine detail clearly. In macular degeneration, it may thin and develop yellow spots; sometimes, abnormal blood vessels grow under it. Diagram shows the side view of an eye and a zoom view of the macula. (Source: Mayo Clinic Health Letter)